1. Field of the Invention
The present invention relates to a technology that detects whether a secure micro is duplicated in a Downloadable Conditional Access System (DCAS) network, and performs an appropriate operation based on a result of the detecting.
This work was supported by the IT R&D program of MIC/IITA. [2007-S-007-01, The development of downloadable conditional access system]
2. Description of Related Art
When users desire to watch a specific program, a Conditional Access System (CAS) in cable networks determines whether to provide a service based on a user authentication and enables only approved user to receive the program.
Since initial CA systems respectively uses different standards depending on each manufacturing company, initial CA systems are incompatible with devices other than a device of a specific manufacturer. Accordingly, since a broadcasting service provider must directly provide subscribers (members) with receiving terminals, burdens on the broadcasting service provider are heavy, and updating the CA system is difficult.
In order to solve the above-described problem, OpenCable of North America announced a standard of separating a CA module from a member terminal. This is for preventing a device manufacturer from monopolizing the market, and for promoting competition, thereby inducing product prices to fall. The CA module separated from the terminal is standardized into a cable card of a Personal Computer Memory Card International Association (PCMCIA) card type, and the broadcasting service provider may provide a paid broadcasting service by providing the subscribers with only cable cards without lending the terminals to the members, similar to the previous scheme. However, since a price of the cable card rises, management cost increases, and a retail market of the terminals is diminished, a result desired by OpenCable is not accomplished.
In this situation, a Downloadable Conditional Access System (DCAS)-related technology of enabling the paid broadcasting service by downloading CA software to a member terminal without separately requiring a hardware CA module is introduced.
In a DCAS technology, an authenticated DCAS host downloads a secure micro client image, and performs a key management function to access a fee-based program using the secure micro client. However, when a secure micro of DCAS host may be duplicated in an inappropriate way, and the secure micro client image may be downloaded using the duplicated secure micro, a DCAS technology may not succeed.
Accordingly, it is required to check whether a DCAS host operates a duplicated secure micro. When it is determined that a DCAS host manages a duplicated secure micro, it is required to deny a program access authority of a corresponding DCAS host. Thus, a technology capable of detecting a duplicated secure micro, and performing an appropriate operation based on a result of the detecting is required.